Methods and systems for reducing blocking artifacts with reduced complexity for spatially-scalable video coding

• US 7,929,610 B2
• Filed: 02/07/2006
• Issued: 04/19/2011
• Est. Priority Date: 03/26/2001
• Status: Active Grant

• Current Assignee: Dolby Laboratories Licensing Corporation (Dolby Laboratories Incorporated)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Sun, Shijun
• Primary Examiner(s): AN, SHAWN S
• Application Number:
  US11/350,181
• Publication Number:
  US 20060126962A1
• Time in Patent Office: 1,897 Days
• Field of Search: 375/240.16, 375/240.13, 375/240.12, 375/240.14, 375/240.15, 375/240.24, 382/235, 382/238, 382/239
• US Class Current: 375/240.16
• CPC Class Codes: H04N 19/117 Filters, e.g. for pre-processing or post-processing sub-band filter banks H04N19/635
• CPC Class Codes: H04N 19/136 Incoming video signal characteristics or properties
• CPC Class Codes: H04N 19/137 Motion inside a coding unit, e.g. average field, frame or block difference
• CPC Class Codes: H04N 19/139 Analysis of motion vectors, e.g. their magnitude, direction, variance or reliability
• CPC Class Codes: H04N 19/14 Coding unit complexity, e.g. amount of activity or edge presence estimation H04N19/146 takes precedence
• CPC Class Codes: H04N 19/159 Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/187 the unit being a scalable video layer
• CPC Class Codes: H04N 19/196 being specially adapted for the computation of encoding parameters, e.g. by averaging previously computed encoding parameters processing of motion vectors H04N19/513
• CPC Class Codes: H04N 19/527 Global motion vector estimation
• CPC Class Codes: H04N 19/573 Motion compensation with multiple frame prediction using two or more reference frames in a given prediction direction
• CPC Class Codes: H04N 19/59 involving spatial sub-sampling or interpolation, e.g. alteration of picture size or resolution
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 19/80 Details of filtering operations specially adapted for video compression, e.g. for pixel interpolation H04N19/635, H04N19/86 take precedence
• CPC Class Codes: H04N 19/82 involving filtering within a prediction loop
• CPC Class Codes: H04N 19/86 involving reduction of coding artifacts, e.g. of blockiness
• CPC Class Codes: H04N 19/895 in combination with error concealment

Abstract

Embodiments of the present invention comprise systems and methods for characterization of block boundaries for filtering operations in spatial scalable video coding. Some embodiments of the present invention comprise methods and systems designed for use with the Scalable Video Coding extension of H.264/MPEG-4 AVC.

Claims

1. A method for characterization of a block boundary between neighboring image blocks within a spatial scalability enhancement layer wherein at least one of said neighboring image blocks is encoded using inter-layer texture prediction, said method comprising:

operating a block identifying portion to identify the neighboring image blocks;

characterizing said block boundary between neighboring image blocks identified by said block identifying portion with a first boundary strength indicator when one of said identified neighboring image blocks is determined to be encoded using an intra-prediction mode other than said inter-layer texture prediction.

2. A method as described in claim 1 further comprising:

characterizing said block boundary between neighboring image blocks identified by said block identifying portion with a second boundary strength indicator when, said identified neighboring image blocks are not encoded using an intra-prediction mode other than said inter-layer texture prediction; and

any of said neighboring image blocks and blocks from which said neighboring image blocks are predicted have non-zero transform coefficients.

3. A method as described in claim 2 further comprising:

characterizing said block boundary between neighboring image blocks identified by said block identifying portion with a third boundary strength indicator when, said identified neighboring image blocks are not encoded using an intra-prediction mode other than said inter-layer texture prediction;

all of said neighboring image blocks and blocks from which said neighboring image blocks are predicted have no transform coefficients; and

said neighboring image blocks are predicted with reference to different reference blocks.

4. A method as described in claim 3 further comprising:

characterizing said block boundary between neighboring image blocks identified by said block identifying portion with a fourth boundary strength indicator when, said identified neighboring image blocks are not encoded using an intra-prediction mode other than said inter-layer texture prediction;

all of said neighboring image blocks and blocks from which said neighboring image blocks are predicted have no transform coefficients; and

said neighboring image blocks are not predicted with reference to different reference blocks.

5. A method as described in claim 4 further comprising applying a deblocking filter to filter said block boundary, the strength of filtering by the deblocking filter being determined by each boundary strength indicator, wherein said first boundary strength indicator triggers more aggressive smoothing by the deblocking filter than said second boundary strength indicator, said second boundary strength indicator triggers more aggressive smoothing by the deblocking filter than said third boundary strength indicator and said third boundary strength indicator triggers more aggressive smoothing by the deblocking filter than said fourth boundary strength indicator when applying the deblocking filter to filter said block boundary.

6. A method as described in claim 2 further comprising applying a deblocking filter to filter said block boundary, the strength of filtering by the deblocking filter being determined by each boundary strength indicator, wherein

said first boundary strength indicator triggers more aggressive smoothing by the deblocking filter than said second boundary strength indicator when applying the deblocking filter to filter said block boundary.

7. A method as described in claim 3 further comprising applying a deblocking filter to filter said block boundary, the strength of filtering by the deblocking filter being determined by each boundary strength indicator, wherein said first boundary strength indicator triggers more aggressive smoothing by the deblocking filter than said second boundary strength indicator and said second boundary strength indicator triggers more aggressive smoothing by the deblocking filter than said third boundary strength indicator when applying the deblocking filter to filter said block boundary.

8. A method as described in claim 1 further comprising:

characterizing said block boundary between neighboring image blocks identified by said block identifying portion with a second boundary strength indicator when, said identified neighboring image blocks are not encoded using an intra-prediction mode other than said inter-layer texture prediction; and

said neighboring image blocks are predicted with reference to different reference blocks.

9. A method as described in claim 8 further comprising applying a deblocking filter to filter said block boundary, the strength of filtering by the deblocking filter being determined by each boundary strength indicator, wherein said first boundary strength indicator triggers more aggressive smoothing by the deblocking filter than said second boundary strength indicator when applying the deblocking filter to filter said block boundary.

10. A system for characterization of a block boundary between neighboring image blocks within a spatial scalability enhancement layer wherein at least one of said neighboring image blocks is encoded using inter-layer texture prediction, said system comprising:

a block identifying portion configured to identify the neighboring image blocks; and

a prediction mode analyzer for characterizing said block boundary between neighboring image blocks identified by said block identifying portion with a first boundary strength indicator when one of said neighboring image blocks is encoded using an intra-prediction mode other than said inter-layer texture prediction.

11. A system as described in claim 10 further comprising:

a coefficient analyzer for characterizing said block boundary between neighboring image blocks identified by said block identifying portion with a second boundary strength indicator when, said neighboring image blocks are not encoded using an intra-prediction mode other than said inter-layer texture prediction; and

any of said neighboring image blocks and blocks from which said neighboring image blocks are predicted have non-zero transform coefficients.

12. A system as described in claim 11 further comprising:

a) a second prediction reference block analyzer for characterizing said block boundary between neighboring image blocks identified by said block identifying portion with a third boundary strength indicator when, i) said neighboring image blocks are not encoded using an intra-prediction mode other than said inter-layer texture prediction;

ii) all of said neighboring image blocks and blocks from which said neighboring image blocks are predicted have no transform coefficients; and

iii) said neighboring image blocks are predicted with reference to different reference blocks.

13. A system as described in claim 12 further comprising:

a block boundary analyzer for characterizing said block boundary between neighboring image blocks identified by said block identifying portion with a fourth boundary strength indicator when, said neighboring image blocks are not encoded using an intra-prediction mode other than said inter-layer texture prediction;

all of said neighboring image blocks and blocks from which said neighboring image blocks are predicted have no transform coefficients; and

said neighboring image blocks are not predicted with reference to different reference blocks.

14. A method as described in claim 13 further comprising a deblocking filter operable to filter said block boundary, the strength of filtering by the deblocking filter being determined by each boundary strength indicator, wherein said first boundary strength indicator triggers more aggressive smoothing by the deblocking filter than said second boundary strength indicator, said second boundary strength indicator triggers more aggressive smoothing by the deblocking filter than said third boundary strength indicator and said third boundary strength indicator triggers more aggressive smoothing by the deblocking filter than said fourth boundary strength indicator when applying the deblocking filter to filter said block boundary.

15. A system as described in claim 11 further comprising a deblocking filter operable to filter said block boundary, the strength of filtering by the deblocking filter being determined by each boundary strength indicator, wherein said first boundary strength indicator triggers more aggressive smoothing by the deblocking filter than said second boundary strength indicator when applying the deblocking filter to filter said block boundary.

16. A method as described in claim 12 further comprising a deblocking filter operable to filter said block boundary, the strength of filtering by the deblocking filter being determined by each boundary strength indicator, wherein said first boundary strength indicator triggers more aggressive smoothing by the deblocking filter than said second boundary strength indicator and said second boundary strength indicator triggers more aggressive smoothing by the deblocking filter than said third boundary strength indicator when applying the deblocking filter to filter said block boundary.

17. A system as described in claim 10 further comprising:

a prediction reference block analyzer for characterizing said block boundary between neighboring image blocks identified by said block identifying portion with a second boundary strength indicator when, said neighboring image blocks are not encoded using an intra-prediction mode other than said inter-layer texture prediction; and

said neighboring image blocks are predicted with reference to different reference blocks.

18. A method as described in claim 17 further comprising a deblocking filter operable to filter said block boundary, the strength of filtering by the deblocking filter being determined by each boundary strength indicator, wherein said first boundary strength indicator triggers more aggressive smoothing by the deblocking filter than said second boundary strength indicator when applying the deblocking filter to filter said block boundary.